Abstract: A very low energy-absorption coating and related methods for use with high power CO2 lasers includes at least a thin layer of ThF4 (16) used as a water/moisture barrier, in combination with BaF2 (14), for various optical elements. When used in connection with a ZnSe substrate (12) or any other suitable material (such as for a focusing lens), the coating (10) extends the useful life by helping prevent moisture adsorption that otherwise may occur within 2-3 days of contact with air. The coating (10) may comprise (1) a BaF2 layer (14) of approximately optical quarter wave thickness, (2) a thin 200-300 Angstrom layer of ThF4 (16) used as a water barrier (3) a thin 1000-2000 Angstrom layer of ZnSe (18), and (4) an optional ZnSe layer (20) of optical half wave thickness. Among other applications, the coating (10) provides very low energy absorption for a 10.6 um CO2 laser at a value<0.15%, and provides longer lifetimes as compared to conventional coated lenses without the combination of BaF2 (14) and ThF4 (16).

Abstract: A very low energy-absorption coating and related methods for use with high power CO2 lasers includes at least a thin layer of ThF4 (16) used as a water/moisture barrier, in combination with BaF2 (14), for various optical elements. When used in connection with a ZnSe substrate (12) or any other suitable material (such as for a focusing lens), the coating (10) extends the useful life by helping prevent moisture adsorption that otherwise may occur within 2-3 days of contact with air. The coating (10) may comprise (1) a BaF2 layer (14) of approximately optical quarter wave thickness, (2) a thin 200-300 Angstrom layer of ThF4 (16) used as a water barrier (3) a thin 1000-2000 Angstrom layer of ZnSe (18), and (4) an optional ZnSe layer (20) of optical half wave thickness. Among other applications, the coating (10) provides very low energy absorption for a 10.6 um CO2 laser at a value<0.15%, and provides longer lifetimes as compared to conventional coated lenses without the combination of BaF2 (14) and ThF4 (16).

Abstract: Disclosed embodiments pertain to optical assemblies which impart a spatially dependent rotation to linearly polarized light. A pair of optical assemblies may be used to apply a spatially dependent rotation to linearly polarized light in the region between the optical assemblies, and produce a spatially independent rotation after traversing the second optical assembly. A pair of optical assemblies may be used in combination with a wave plate to allow a determination of the Stokes parameters of an elliptically polarized beam of light.

Abstract: Disclosed embodiments pertain to optical assemblies which impart a spatially dependent rotation to linearly polarized light. A pair of optical assemblies may be used to apply a spatially dependent rotation to linearly polarized light in the region between the optical assemblies, and produce a spatially independent rotation after traversing the second optical assembly. A pair of optical assemblies may be used in combination with a wave plate to allow a determination of the Stokes parameters of an elliptically polarized beam of light.